Magnetic storage systems, such as a hard disk drive (HDD), are utilized in a wide variety of devices in both stationary and mobile computing environments. Examples of devices that incorporate magnetic storage systems include desktop computers, portable notebook computers, portable hard disk drives, digital versatile disc (DVD) players, high definition television (HDTV) receivers, vehicle control systems, cellular or mobile telephones, television set top boxes, digital cameras, digital video cameras, video game consoles, and portable media players.
A typical disk drive includes magnetic storage media in the form of one or more flat disks or platters. The disks are generally formed of two main substances, namely, a substrate material that gives it structure and rigidity, and a magnetic media coating that holds the magnetic impulses or moments that represent data. Such typical disk drives also typically include a read head and a write head, generally in the form of a magnetic transducer, which can sense and/or change the magnetic fields stored on the disks or media. Perpendicular magnetic recording (PMR) involves recorded bits that are stored in a generally planar recording layer, but in a generally perpendicular or out-of-plane orientation with respect to the recording layer. A PMR read head (reader) and a PMR write head (writer) are usually formed as an integrated read/write head along an air-bearing surface (ABS). In a PMR reader, a magnetoresistive (MR) sensor or transducer is frequently employed in the read head, and the write head includes a write pole for directing a magnetic field to the recording layer of a magnetic recording medium or stack.